The present embodiments relate to ultrasound transducers. In particular, whether the transducer performs properly is determined.
Ultrasound diagnostic imaging and therapy use arrays of transducer elements. During manufacture, one or more elements may be defective, such as due to shorting, inoperable driver, faulty connection, delamination of element layers, or other defect. Due to use, one or more elements may become defective, such as due to dropping, wear, or other damage.
For a one dimensional array, such as of 64-128 elements, one or more inoperable or otherwise poor performing elements may result in undesired imaging artifacts. As a result, any defective elements are undesired. In larger arrays, such as those becoming more common with two-dimensional (2D) arrays, some elements may typically be defective, either initially due to manufacturing defects or after some time due to degradation or damage. Usually, it is acceptable if some amounts of these elements are non-functional, especially if the defective elements are sparsely populated. If several elements in one area are defective, the overall array may not be acceptable due to side lobes or loss of sensitivity when certain apertures are selected.
To test for defective elements, special test equipment is used. For example, a transducer may be positioned in a liquid-filled tank and the acoustic output of each element is measured with a hydrophone. This time consuming and cumbersome external testing may be sufficient during manufacturing, but not optimal, for one-dimensional arrays. For 2D arrays or for measurements of any array in the medical environment, this approach may not be possible or desired. Given thousands of elements of a 2D array, testing may be slow even if attempted during manufacture.